HP India — Airtel dongle offer on addl. payment of Rs. 1999/- on purchase of HP Notebook

Hi I have purchased a HP 15-af024AU APU Quad Core A8 - (4 GB DDR3/1 TB HDD/Windows 8.1) Notebook (15.59 inch, Turbo SIlver Color With Diamond & Cross Brush Pattern) form Flipkart on August 2nd 2015 vide Order IDOD[protected] . I have paid the complete amount through online. The HP offered Airtel 4g dongle and other articles for payment of additional Rs.1999/- (actually in Flipkart they shown Rs. 1499/- only). Eventhough, I paid Rs. 1999/- along with required documents pertains to Laptop. About 10 days back I received Email from HP redemption authorities about Airtel dongle with a condition of purchase of postpaid connection greater than Rs. 450/-. When I approached Airtel dealer in Nalgonda, they informed that to claim my offer I have to purchase post paid connection greater than Rs. 450/- for 6 months duration. Imagine... what is this offer. This is really a kind of deceiving the customers and I want justice and need...